Steam-boiler



i UNITED STATES PATENT FFTCE.

JAMES S. COLVIN, F PITTSBURG, PENNSYLVANIA.

STEAM-BOITIER.

Specification of Letters Patent No. 28,657, dated June 12, 1860.

. Toall whom fit may concern:

Be it known that I` J. S. CoLvrN, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improved Steam-Boiler and Furnace; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the annexed drawing, forming part of this specification, in which- Figure l, is an exterior view of my improved boiler and furnace. Fig. 2, is a vertical section thereof. Fig. 3, is a transverse or horizontal section through the boiler at m-:c Fig. l. Fig. 4, is a horizontal section through the furnace at m ae-a: as Fig. 1.

In the several figures like letters of reference denote similar parts of the appara-tus.

My improvement is designed to effect asaving of fuel by such a construction and` arrangement of furnace in connection with a. steam boiler as to communicate a greater quantity of heat to a given quantity of air,

'than by the means ordinarily employed, and

to circulate the heated air in such a manner through the boiler as to extract a greater portion of its caloric before it is allowed to pass olf, by dispensing with the ordinary chimney draft, and compelling` the air to pass downward as it cools, and as its place is supplied by the blast of hot air from the furnace, until it escapes at the flue. Also in so arranging the furnace in relation to the boiler as that the bottom of the boiler shall not be exposed to the direct action of the fire, but that the greatest degree of heat shall be applied near to the surface of the water where it is hottest, the cold feed water being introduced at the bottom of the boiler, where it is coldest, and being gradually heated, as it rises to the surface. By this arrangement also, the danger which arises from the incrustation of the bottom of the boiler, and the induration of the sediment is avoided, thus preventing the burning out of the bottom of the boiler, and the consequent danger of explosion, and loss of heat.

To enable others skilled in the art to construct and use my improved furnace and boiler, I will proceed to describe its construction and operation. Y

In the drawing a is the boiler, which is cylindrical and vertical, having a flat bottom b and a hemispherical top or dome c. It is constructed of sheets of boiler iron in the usual manner. The bottom of the boiler has a large circular opening, connecting with a smaller vertical (c) cylinder e placed underneath the boiler, in which is placed the furnace A. Around t-he boiler a is a cylindrical casing f, which is closed around the boiler, at the height of the water line, or a little above it (as seen in Fig. 2). This casing f is made of iron, and is concentric with theh boiler, leaving a free space all around the sides of the boiler and under it, from the circumference to the outside of the vertical cylinder c which surrounds the furnace. This casing f also extends down over the vertical cylinder e surrounding it, except for a short space, left to admit of access to the furnace; it also extends under the furnace cylinder, thus completely enveloping the boiler from the water line downward, and the furnace cylinder (with the exception just named) and leaving a space sufficient to allow the free passage of the products of combustion to pass downward between this casing or acket f, and the boiler and furnace; (as seen in Fig. 2.) Through this space K between the casing and the exterior of the boiler and furnace, the smoke and gases, and othei` products of combustion of the furnace, pass to the Hue C, which opens into the space K. near the bottom of the furnace. A damper g placed near the mouth of the flue C serves to regulate the escape of smoke, &c., up the flue. The flue rises perpendicularly to carry off the smoke and air from the furnace, as hereinafter described. n

Inside of the boiler mis a cylinder B, traversed by a number of tubes L, h of from one and a half to five inches in diameter, varying with the size of the boiler, which tubes are fastened at each end, to the top and bottom of the cylinder B and are themselves open at both ends, the upper end opening into the dome D, of the boiler, and the lower end opening into the water space, between the bottom of the cylinder and the bottom of the boiler. The bottom of the cylinder B is raised some inches above the bottom of the boiler. There are also a number of small pipes z', z', &c., extending vertically from the bottom of the cylinder B to the bottom Z) of the boiler, which are open at bo'th ends, so as to connect the inside of the cylinder B, with the cavity K between the bottom b of the boiler and the casing lVith the exception of the tubes h, h and pipes z' z' (the latter opening into the interior of the cylinder B, and the former passing through, but not opening into it,) and the aperture I, at the throat of the furnace the cylinder B is closed at top and bottom. Small connecting pipes j, j, &c., near the top, and similar connecting pipes j y" near the bottom of the cylinder B open a connection from its interior to the cavity K around the boiler a formed by the acket or casing f.

The furnace A is situate inside of the cylinder e which surrounds, but does not come in contact with the furnace. This furnace is small compared with the size of the boiler. It is made of iron lined throughout with fire brick. It is cylindrical, its vertical length or height being greater than its diameter. It is set immediately under the center of the boiler, though that is not necessary, as it may be placed on one side, if more convenient, and if necessary several furnaces constructed as hereinbefore described, and so connected with the boiler as to produce the same effect, may be employed.

The diameter of the furnace, is equal throughout up to the height of the bottom of the boiler or thereabout, from which point it contracts upward toward the bottom of the cylinder B, where its throat is about half the diameter of the cylindrical part, as at I Fig. 2. The diameter' of the throat of the chimney at I corresponds with the center of the bottom plate of the cylinder B which rests on the top of the furnace, (as seen in Fig. 2,) so that the heated air and products of combustion of the furnace, pass at once into the interior of the cylinder B.

H is the bars of the furnace on which the coals rest, and under the bars a few inches below, is a sliding grating Gr which is opened or closed at pleasure by a slide 7c, for the purpose of allowing the discharge of ashes, cinders &c., which fall from the lire. Below the sliding grating at m is an opening to allow of removal of ashes from the ash pit, and above the grate bars at Z is a similar opening for kindling the lire, cleaning out the grate, &c. These openings are kept tightly closed when the furnace is at work, by caps or Stoppers n, n. Between the grate bars I'I and sliding grating G is a pipe E, which enters the furnace from without, and supplies a blast of fresh air to the fire, which is forced in by a fan or otherwise. Fuel in the form of broken coal (or other fuel in small pieces) is supplied from time to time, through the inclined spout F, which is, at other times, kept closed to prevent the escape of the products of combustion of the furnace.

The feed water is supplied to the boiler through a pipe at p, the water passing into the space around the furnace cylinder, thence into the water space S in the boiler, under the cylinder B, and up around the cylinder B and into, and a little above, the

top of the tubes z, in the cylinder. The heated air passes from the furnace into the cylinder B there surrounding the tubes h h (which are filled with water) and passes through the openings j, j, into the space between the boiler and its casing or jacket f, downward till it escapes, deprived of a great portion of its heat, at the pipe C.

Having thus described the construction of my improved boiler and furnace, it remains to explain the mode of its operation.

The principle upon which my improvements are based, is that the greatest economy of fuel is attained by consuming it at the highest possible temperature, for by charging a small quantity of air with a large quantity of heat, and then allowing that heat to be extracted by the water in the boiler, the air when `it has parted with as much of its heat as possible, will carry olf a smaller quantity of heat than a larger quantity of air at the same temperature would do, and hence a great saving of heat, and consequently of fuel. This I accomplish by the use of the comparatively small furnace, lined with fire brick, and so arranged as vbefore described, as to exclude the external air, excepting through the opening at E, where the air is forced in by a moderate blast, which may be regulated at pleasure. Here a thorough combustion is produced with intense heat, and the air having no vother escape than through the body of coal in the grate, passes up into the interior of the cylinder B and circulates around the water pipes 7L h, &c. This mode of heating would soon destroy those parts of the boiler furnace which come in contact with the fire, but by lining my furnace with fire brick and surrounding it with water in the space K, this diliiculty is obviated. The heated air being forced through the contracted throat of the furnace at I rises to the top of the cylinder B, where it acts at once on the hottest water in the boiler, which will be at the top of the tubes, and lying a few inches deep on the top of the cylinder B. Thus the heat of the furnace acts not as in boilers of the ordinary construction, at the points nearest to the furnace, but at the point farthest from it that is near the top of the cylinder B and steam is not only more rapidly generated, but being formed nearer tothe surface of the water, it is not so much charged with water imperfectly vaporized. At the same time the water lower downin the tubes h L, &c., is gradually heated by the hot air in the cylinder B and rises to the top; being exposed to the greatest degree of heat, at the Y top of the cylinder.

In boilers of ordinary construction, the heat of the furnace is kept up and increased by the draft; but this draft is caused bythe tendency of the hot air to rise, and thus the greater the draft, the more rapidly does the lli so 'l 4 11o 115 1 i t hot air pass 0H, whereby a great loss of heat and waste of fuel is induced. By my improvement, however, I reverse this arrangement, create the necessary draft to furnish oxygen for the combustion of the fuel by artificial means, and provide for the escape of the products of combustion, not by allowing the heated air to rise and pass off, but by allowing the air as it loses its caloric, to sink below the heated air which enters from the furnace, until it gets to the bottom of the outer casing, when having parted with a great proportion of its caloric, it enters the chimney or flue, and is carried off, the damper at the mouth of the flue preventing the too rapid escape of the heated air.

The water line of my boiler, is about ten inches above the top of the inner cylinder; the water occupying the space around and under t-he furnace, also the space between the bottom of the cylinder B and the bottom of the boiler, and around the cylinder inside the boiler, and lling the tubes h h in the cylinder. These water spaces all communicate freely, and in all of them the water is more or less exposed to the heat. The steam is collected in the dome D of the boiler.

The heated air and products of combustion of the furnace, as before stated, are forced through the contracted throat I of the furnace, and pass rapidly upward to the top of the cylinder. In doing so, the heated air, &c., heats the water in the tubes la, L, &c., and around the cylinder, but the top of the cylinder becomes the hottest. As the air parts with its caloric, some of it passes through the upper apertures j j into the space between the boiler and its casing, while the remainder descends in the cylinder B to give place to the hotter air rising from the furnace. The air in descending cont-inues to part with its caloric to the water in the tubes, until it passes out of the cylinder B through the pipes i z or the side apertures j y" into the space made by the casing under the boiler. Thence the air` passes around the furnace and out through the flue C as before stated.

In marine boilers, where it is desirable to have the outer casing of the boiler of brick, it need not extend so high up as the water line, and then the upper openings j, j, are dispensed with, and the brick casing will be closed around the boiler above the lower openings j j.

The pipes z' z', &c., not only allow the downward currentof air, but permit any dust or ashes which may be blown into the cylinder B from the furnace, to fall down into the space K under the boiler, whence they are carried of to the flue C.

Another great advantage of my boiler, is

that the calcareous or other deposit, which settles on the bottom of the boiler (on the level of which, the blow o is situate) may be readily removed by emptying the boiler, because as the bottom of the boiler is not (as in ordinary boilers) exposed to the direct action of the fire, nor to the greatest heat, it will not so soon become indurated, but will mix with the discharging water, and pass off, and thus a fruitful cause of accident, and the speedy burning out of the boiler bottom, is removed.

Having thus described my improvement in boilers what I claim as my invention, and desire to secure by Letters Patent, is:

1. The combination and arrangement hereinbefore described of the small air tight furnace, supplied with a blast of air with a heating cylinder inside of a steam boiler in the manner substantially as hereinbefore described, for the purpose of securing the more uniform distribution of the heat of the furnace than is practicable, when the bottom of the boiler is exposed to the direct action of the fire, so that the greatest degree of heat shall be applied near to the surface of the water in the boiler.

2. Placing the escape flue for the air and products of combustion of the furnace, in the position in relation to the furnace and boiler, substantially as described so that the air and products of combustion gradually descend as they part with their heat, until they find their exit at the lowest point, thus preventing the escape of the products of combustion, until they have parted with as much as practicable of their excess of caloric, and thus by economizing heat, eecting a great saving of fuel.

3. Connecting the furnace of the boiler with a heating chamber inside the boiler, by means of the confined throat of the fire chamber, substantially as described, so that the furnace being air tight, and supplied with a blast, forces the heated air to rise directly to the top of the heating chamber, and thus apply the greatest heat near to the surface of the water, for the purpose of securing the more rapid generation of steam.

In testimony whereof, the said J. S. CoL- VIN hath hereunto set his hand.

JAMES S. COLVIN.

Witnesses:

W. BAKEwELL, M. Gr. CUSHING. 

